From b38b680dae24d00dd580db3899bcc8142f75fa53 Mon Sep 17 00:00:00 2001 From: Roxana Nicolescu Date: Thu, 9 Apr 2026 14:43:26 +0200 Subject: [PATCH 1/3] net: atm: add lec_mutex jira VULN-163327 cve CVE-2025-38323 commit-author Eric Dumazet commit d13a3824bfd2b4774b671a75cf766a16637a0e67 syzbot found its way in net/atm/lec.c, and found an error path in lecd_attach() could leave a dangling pointer in dev_lec[]. Add a mutex to protect dev_lecp[] uses from lecd_attach(), lec_vcc_attach() and lec_mcast_attach(). Following patch will use this mutex for /proc/net/atm/lec. BUG: KASAN: slab-use-after-free in lecd_attach net/atm/lec.c:751 [inline] BUG: KASAN: slab-use-after-free in lane_ioctl+0x2224/0x23e0 net/atm/lec.c:1008 Read of size 8 at addr ffff88807c7b8e68 by task syz.1.17/6142 CPU: 1 UID: 0 PID: 6142 Comm: syz.1.17 Not tainted 6.16.0-rc1-syzkaller-00239-g08215f5486ec #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xcd/0x680 mm/kasan/report.c:521 kasan_report+0xe0/0x110 mm/kasan/report.c:634 lecd_attach net/atm/lec.c:751 [inline] lane_ioctl+0x2224/0x23e0 net/atm/lec.c:1008 do_vcc_ioctl+0x12c/0x930 net/atm/ioctl.c:159 sock_do_ioctl+0x118/0x280 net/socket.c:1190 sock_ioctl+0x227/0x6b0 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Allocated by task 6132: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4328 [inline] __kvmalloc_node_noprof+0x27b/0x620 mm/slub.c:5015 alloc_netdev_mqs+0xd2/0x1570 net/core/dev.c:11711 lecd_attach net/atm/lec.c:737 [inline] lane_ioctl+0x17db/0x23e0 net/atm/lec.c:1008 do_vcc_ioctl+0x12c/0x930 net/atm/ioctl.c:159 sock_do_ioctl+0x118/0x280 net/socket.c:1190 sock_ioctl+0x227/0x6b0 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6132: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2381 [inline] slab_free mm/slub.c:4643 [inline] kfree+0x2b4/0x4d0 mm/slub.c:4842 free_netdev+0x6c5/0x910 net/core/dev.c:11892 lecd_attach net/atm/lec.c:744 [inline] lane_ioctl+0x1ce8/0x23e0 net/atm/lec.c:1008 do_vcc_ioctl+0x12c/0x930 net/atm/ioctl.c:159 sock_do_ioctl+0x118/0x280 net/socket.c:1190 sock_ioctl+0x227/0x6b0 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+8b64dec3affaed7b3af5@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/6852c6f6.050a0220.216029.0018.GAE@google.com/T/#u Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20250618140844.1686882-2-edumazet@google.com Signed-off-by: Jakub Kicinski (cherry picked from commit d13a3824bfd2b4774b671a75cf766a16637a0e67) Signed-off-by: Roxana Nicolescu --- net/atm/lec.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/atm/lec.c b/net/atm/lec.c index 9b99d8ae48df4..45b69737115bd 100644 --- a/net/atm/lec.c +++ b/net/atm/lec.c @@ -124,6 +124,7 @@ static unsigned char bus_mac[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }; /* Device structures */ static struct net_device *dev_lec[MAX_LEC_ITF]; +static DEFINE_MUTEX(lec_mutex); #if IS_ENABLED(CONFIG_BRIDGE) static void lec_handle_bridge(struct sk_buff *skb, struct net_device *dev) @@ -686,6 +687,7 @@ static int lec_vcc_attach(struct atm_vcc *vcc, void __user *arg) int bytes_left; struct atmlec_ioc ioc_data; + lockdep_assert_held(&lec_mutex); /* Lecd must be up in this case */ bytes_left = copy_from_user(&ioc_data, arg, sizeof(struct atmlec_ioc)); if (bytes_left != 0) @@ -711,6 +713,7 @@ static int lec_vcc_attach(struct atm_vcc *vcc, void __user *arg) static int lec_mcast_attach(struct atm_vcc *vcc, int arg) { + lockdep_assert_held(&lec_mutex); if (arg < 0 || arg >= MAX_LEC_ITF) return -EINVAL; arg = array_index_nospec(arg, MAX_LEC_ITF); @@ -726,6 +729,7 @@ static int lecd_attach(struct atm_vcc *vcc, int arg) int i; struct lec_priv *priv; + lockdep_assert_held(&lec_mutex); if (arg < 0) arg = 0; if (arg >= MAX_LEC_ITF) @@ -743,6 +747,7 @@ static int lecd_attach(struct atm_vcc *vcc, int arg) snprintf(dev_lec[i]->name, IFNAMSIZ, "lec%d", i); if (register_netdev(dev_lec[i])) { free_netdev(dev_lec[i]); + dev_lec[i] = NULL; return -EINVAL; } @@ -1004,6 +1009,7 @@ static int lane_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) return -ENOIOCTLCMD; } + mutex_lock(&lec_mutex); switch (cmd) { case ATMLEC_CTRL: err = lecd_attach(vcc, (int)arg); @@ -1018,6 +1024,7 @@ static int lane_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) break; } + mutex_unlock(&lec_mutex); return err; } From 6aebf64197c9d6dc6f9f0e6a3a90ff4174de0117 Mon Sep 17 00:00:00 2001 From: CIQ Kernel Automation Date: Thu, 9 Apr 2026 06:44:08 +0000 Subject: [PATCH 2/3] net: atm: fix /proc/net/atm/lec handling jira VULN-163377 cve CVE-2025-38180 commit-author Eric Dumazet commit d03b79f459c7935cff830d98373474f440bd03ae /proc/net/atm/lec must ensure safety against dev_lec[] changes. It appears it had dev_put() calls without prior dev_hold(), leading to imbalance and UAF. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Acked-by: Francois Romieu # Minor atm contributor Link: https://patch.msgid.link/20250618140844.1686882-3-edumazet@google.com Signed-off-by: Jakub Kicinski (cherry picked from commit d03b79f459c7935cff830d98373474f440bd03ae) Signed-off-by: CIQ Kernel Automation --- net/atm/lec.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/atm/lec.c b/net/atm/lec.c index 45b69737115bd..fd8f88a1b314a 100644 --- a/net/atm/lec.c +++ b/net/atm/lec.c @@ -910,7 +910,6 @@ static void *lec_itf_walk(struct lec_state *state, loff_t *l) v = (dev && netdev_priv(dev)) ? lec_priv_walk(state, l, netdev_priv(dev)) : NULL; if (!v && dev) { - dev_put(dev); /* Partial state reset for the next time we get called */ dev = NULL; } @@ -934,6 +933,7 @@ static void *lec_seq_start(struct seq_file *seq, loff_t *pos) { struct lec_state *state = seq->private; + mutex_lock(&lec_mutex); state->itf = 0; state->dev = NULL; state->locked = NULL; @@ -951,8 +951,9 @@ static void lec_seq_stop(struct seq_file *seq, void *v) if (state->dev) { spin_unlock_irqrestore(&state->locked->lec_arp_lock, state->flags); - dev_put(state->dev); + state->dev = NULL; } + mutex_unlock(&lec_mutex); } static void *lec_seq_next(struct seq_file *seq, void *v, loff_t *pos) From e8b19b9a4213cfb7ca404603c9e909ef1e189993 Mon Sep 17 00:00:00 2001 From: CIQ Kernel Automation Date: Thu, 9 Apr 2026 06:45:02 +0000 Subject: [PATCH 3/3] netfilter: nf_tables: fix use-after-free in nf_tables_addchain() jira VULN-177697 cve CVE-2026-23231 commit-author Inseo An commit 71e99ee20fc3f662555118cf1159443250647533 nf_tables_addchain() publishes the chain to table->chains via list_add_tail_rcu() (in nft_chain_add()) before registering hooks. If nf_tables_register_hook() then fails, the error path calls nft_chain_del() (list_del_rcu()) followed by nf_tables_chain_destroy() with no RCU grace period in between. This creates two use-after-free conditions: 1) Control-plane: nf_tables_dump_chains() traverses table->chains under rcu_read_lock(). A concurrent dump can still be walking the chain when the error path frees it. 2) Packet path: for NFPROTO_INET, nf_register_net_hook() briefly installs the IPv4 hook before IPv6 registration fails. Packets entering nft_do_chain() via the transient IPv4 hook can still be dereferencing chain->blob_gen_X when the error path frees the chain. Add synchronize_rcu() between nft_chain_del() and the chain destroy so that all RCU readers -- both dump threads and in-flight packet evaluation -- have finished before the chain is freed. Fixes: 91c7b38dc9f0 ("netfilter: nf_tables: use new transaction infrastructure to handle chain") Signed-off-by: Inseo An Signed-off-by: Florian Westphal (cherry picked from commit 71e99ee20fc3f662555118cf1159443250647533) Signed-off-by: CIQ Kernel Automation --- net/netfilter/nf_tables_api.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 79c27c7a1d61c..a23fe136fbdae 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -2479,6 +2479,7 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask, err_register_hook: nft_chain_del(chain); + synchronize_rcu(); err_chain_add: nft_trans_destroy(trans); err_trans: